A communication monitor that predicts the degrees of importance of alarms developing in a network is known as an operational management system for a network. The communication monitor uniformly manages the alarms with linking the alarms to the alarm types and the alarm importance degrees of in a table, for example, an alarm 1 is linked to a severe failure and an alarm 2 is linked to a mild failure. Thus, when the alarm type is the alarm 1, the communication monitor refers to the table so as to determine the alarm importance degree corresponding to the alarm 1, for example, the severe failure. When the alarm importance degree has been determined as a severe failure, the communication monitor notifies the alarm to the user depending on the alarm importance degree.
Patent Document 1: Japanese Laid-open Patent Publication No. 2009-10438
Patent Document 2: Japanese Laid-open Patent Publication No. 2005-285040
However, the communication monitor fixedly manages the alarm type that identifies the contents of the alarm and the alarm importance degree that identifies the degree of importance of the alarm with uniformly linking the alarm type to the alarm importance degree. Thus, even when an alarm actually has a low alarm importance degree, referring to the table causes the alarm to be notified to the user as an alarm having a high alarm importance. For example, when a congestion failure is caused by a large variation of traffic, changing the path just post the occurrence of the congestion failure gets the traffic back to normal, for example, the traffic immediately recovers from the congestion failure. In such a case, the congestion failure does not necessarily affect the service. Thus, it can also be said that it is not necessary to notify an alarm to the user.